1. Field of the Invention
This invention relates to the field of electronic and opto-electronic devices that rely upon quantum-wire structures for charge transport between device components as well as for charge transport within active wire-like elements of device components.
2. Description of the Prior Art
As originally proposed by H. Sakaki in the Japanese Journal of Applied Physics, 19, L735, 1980, the predicted high mobilities of quasi-one-dimensional wire-like regions of semiconducting material underlie many proposed quantum-wire system concepts. Such a system concept is the quantum-wire array described by H. Sakaki in the Japanese Journal of Applied Physics, 28, L314, 1989. Enhanced carrier mobility is achieved in the subject quantum-wire array by engineering the minibands of the array so that longitudinal-optical (LO) phonon transitions are forbidden. As a second example of the utility of the semiconductor quantum wire is found in S. Luryi and F. Capasso, Applied Physics Letters, 47, 1347, 1985, in which a novel three-terminal resonant-tunneling structure is based on resonant tunneling of a two-dimensional electron gas into a gated one-dimensional quantum wire to produce a negative transconductance. The experimental realization of such a device would portend applications for low-power logic circuits. Quantum wire arrays have also been considered as potential low-current-threshold semiconductor lasers; in fact, there have been indications of strong optical anisotropy in such quantum-wire arrays as reported by M. Tsuchiya, J. M. Gaines, R. H. Yan, R. J. Simes, P. O. Holtz, L. A., Coldren, and P. M. Petroff, Physical Review Letters, 62, 466, 1989. Other efforts on the fabrication and characterization of quantum-wire structures have been reported by M. A. Reed, J. N. Randall, R. J. Aggarwal, R. J. Matyi, T. M. Moore, and A. E. Wetsel, Physical Review Letters, 60, 535, 1988 in connection with quantum-coupled electron device architectures and by M. Watt, C. M. Sotomayer Torres, H. E. G. Arnot, and S. P. Beaumont, Semiconductor Science and Technology, 285, 1990.
Recently, however, theoretical studies of the interaction between LO phonons and carriers in polar-semiconductor quantum wires, such as M. A. Stroscio, Physical Review, B40, 6428, 1989, have revealed the presence of discrete LO phonon modes similar to those identified earlier for polar-semiconductor quantum wells as discussed recently by N. Mori and T. Ando in Physical Review, B40, 6175, 1989. As for quantum wells, interface LO phonons are established at the semiconductor-semiconductor boundaries of quantum wires as described by K. W. Kim, M. A. Stroscio, A. Bhatt, R. Mickevicius and V. V. Mitin in the Journal of Applied Physics, 70, 319, 1991 where interface-phonon scattering effects are demonstrated to be a major source of scattering for electrons confined in the extreme quantum limit for wires with lateral dimensions less than about 40 Angstroms. As recently demonstrated by M. A. Stroscio, G. J. Iafrate, K. W. Kim, M. A. Littlejohn, H. Goronkin and G. N. Maracas in Applied Physics Letters, 59, 1093, 1991, interface-phonon scattering is a major contributor to carrier scattering in superlattices with structure dimensions of about 150 Angstroms or less. Experimental evidence for the enhancement of carrier-interface-phonon scattering as quantum well dimensions are reduced has been reported by K. T. Tsen, D. S. Smith, S. C. Y. Tsen, N. S. Kumar, and H. Morkoc in the Journal of Applied Physics, 70, 418, 1991. This enhanced inelastic carrier-interface-phonon scattering for confinement dimensions of less than roughly 100 Angstroms is undesirable since it reduces carrier mobility. Recent progress in the area of epitaxially-matched, metal to semiconductor interfaces in quantum-well devices has been made. J. P. Harbison, T. Sands, N. Tabatabaie, W. K. Chan, L. T. Florez, and V. G. Kermidas have reported on structures containing such metal-semiconductor interfaces in Applied Physics Letters, 53, 1717, 1988 and in the Journal of Crustal Growth, 95, 425, 1989. Additional papers reporting such results are A. Givarclh, J. Caulet, B. Guernais, Y. Ballini, R. Guerin, A. Poudoulec and A. Regreny in the Journal of Crustal Growth, 95, 427, 1989 and N. Tabatabaie, T. Sands, J. P. Harbison, H. L. Gilchrist and V. G. Kermidas in Applied Physics Letters, 53, 2528, 1988.